Malware

What is Malware?

Malware is a term used to describe software that’s intentionally created to disrupt systems, gain unauthorized access, steal data, or cause other harm to individuals and organizations. It includes a range of digital threats—from simple viruses to complex ransomware campaigns—that can infiltrate devices through various delivery methods and often operate without immediate detection.

Malware is a central concern in cybersecurity due to its versatility and growing sophistication. It’s used by cybercriminals to execute attacks for financial gain, espionage, sabotage, or system control.

Malware Overview

Malware plays a central role in today’s cyberattack landscape. It’s not tied to a single method or outcome, and its delivery can occur through nearly any digital channel: email attachments, compromised websites, rogue USB devices, infected software downloads, and even legitimate-looking apps.

Modern malware is often designed to be stealthy and persistent. It may be part of a larger, multi-stage attack or operate in coordination with other tools in an attacker’s arsenal. Some variants wait silently for instructions, while others immediately begin encrypting data or siphoning sensitive information.

Cybersecurity defenses must address malware at multiple layers. DNS filtering, for example, helps organizations proactively block access to known malicious domains—cutting off threats before malware has a chance to be delivered or communicate with its operators. 

Types of Malware

• Viruses
  These infect files or programs and replicate when those files are run. They typically require user interaction to spread, such as downloading a file attachment and then opening that file.
  
  
• Worms
  Self-replicating programs that can spread without user action by exploiting vulnerabilities in networks or systems. Worms do not necessarily need user interaction to spread across a network.
  
  
• Trojans
  Trojans are a type of virus, named for the “Trojan Horse” in Greek mythology. They appear to be legitimate software but contain hidden code designed to install additional malware or grant remote access. However, Trojans are usually not self-replicating.
  
  
• Ransomware
  Encrypts files or systems and demands payment to restore access. It’s one of the most financially damaging forms of malware. For more on how this threat intersects with other attack vectors, see our article on ransomware, malware, and phishing trends.
  
  
• Spyware and Keyloggers
  Designed to secretly observe user activity, collect credentials, or log keystrokes without consent. These programs do not spread, as with worms or viruses, because the intent is to gather information for exploitation or gain access to a user’s accounts.
  
  
• Botnets
  Networks of malware-infected devices controlled by attackers, often used for large-scale operations like DDoS attacks or spam campaigns. Each infected device is referred to as an individual “bot.” Botnets may be created by Trojans or other methods and deploy spyware onto certain bots. In this scenario, a previously benign device could be controlled by a threat actor without the computer owner being aware of the hijacking. It is up to the threat actor what action each bot might take.

How Malware Spreads

Malware can infect systems in a variety of ways—many of which depend on user behavior, weak defenses, or insecure environments. Common sources of infection include:

• Clicking on links or attachments in phishing emails
  
  
• Visiting malicious or compromised websites
  
  
• Downloading pirated or tampered software
  
  
• Using USB drives or other physical media already infected with malware
  
  
• Operating outdated systems with known security vulnerabilities
  
  
• Misconfigured firewalls, access permissions, or lack of endpoint protection

For guidance on how to prevent malware attacks, organizations should invest in layered defenses—especially those that stop malware at the network edge before payloads are delivered.

What Malware Can Do

Once installed, malware can create serious disruptions and security failures. Its effects may range from short-term inconvenience to lasting financial and reputational damage. Common consequences include:

• Theft of sensitive information, such as credentials, customer data, or intellectual property
  
  
• Downtime, often caused by systems being encrypted, disabled, or repurposed
  
  
• Financial loss due to extortion, fraud, or the cost of system recovery
  
  
• Loss of trust with customers, partners, and regulators
  
  
• Unauthorized access to networks, often used for further exploitation 
  
  
• Violations of compliance regulations, especially in healthcare, finance, or government sectors

Despite its severity, malware can often be prevented through layered security. Blocking malicious domains and ensuring systems are regularly patched reduces both exposure and impact. Many DNS-based threats bypass traditional firewalls, which is why domain-level protections are essential.

Malware vs. Other Threats

Certain cybersecurity terms—like phishing, Trojans, and worms—are often used interchangeably with malware, but they aren’t all equivalent. Some are specific types of malware, while others describe methods of delivery or underlying system weaknesses. Understanding how these terms relate helps clarify both threat classification and defense strategies.

Malware Statistics

• $57 Billion in Annual Ransomware Damages by 2025 - Global ransomware damages are projected to reach $57 billion in 2025. This growth is fueled by increasingly sophisticated attacks, often leveraging AI to enhance their effectiveness.
  
  
• Global ransomware damages are projected to exceed $275 billion annually by 2031. This dramatic rise reflects growing attack volumes, expanding target surfaces, and the adoption of AI and automation by threat actors.
  
  
• Healthcare Sector Remains a Prime Target - In 2024, the healthcare industry continued to be a top target for cybercriminals, experiencing a significant uptick in hacking incidents. System intrusions, including ransomware attacks, have become the leading cause of healthcare data breaches.
  
  
• Ransomware attacks, across all industries, increased by 37% in 2024. Small and medium-sized business are the most vulnerable to ransomware attacks, making up 88% of all attacks.

Examples of Malware in Action

Real-World Examples

• Roaming Mantis – A mobile malware campaign that uses DNS manipulation and phishing to target Android users across regions, combining credential theft with DNS hijacking tactics.
  
  
• WannaCry – A ransomware attack that locked down hundreds of thousands of systems worldwide in 2017 by exploiting a known Windows vulnerability. It disrupted hospitals, governments, and transportation systems.
  
  
• Emotet – Originally a banking Trojan meant to steal sensitive information, later adapted into a malware loader capable of delivering other threats, including ransomware and credential stealers.
  
  
• TrickBot – Known for its modular design, TrickBot is a Trojan that targets Windows systems. It can steal banking details, map networks, and open pathways for further attacks.
  
  
• Malicious WordPress Redirects – Attackers often compromise outdated or insecure WordPress sites to redirect visitors to malware-laden domains. DNS filtering can prevent users from landing on these sites.
  

Stop Malware Before It Reaches Your Network

Most malware attacks begin with a connection—often to a domain that looks harmless at first glance. DNSFilter’s Malicious Domain Protection, botnet, and malware categories block those connections before they can be established, preventing malware payloads from ever reaching your network.

Powered by AI and real-time threat analysis, DNSFilter detects and blocks known and newly registered domains used in malware distribution, command-and-control activity, and phishing campaigns. That means your users are protected, even when they’re off-network or working remotely.

Stay ahead of evolving threats with DNS-layer security that neutralizes malware at its source.

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